Fan



Aug. 11, 1936. E A FREE; 2,050,523

FAN

Filed July 8, 1955 INVENTOR Patented Aug. H, 1936 can D STATES OFFlC 3 Claims.

My invention relates to fans and particularly to that class of fans which are used with the present type of warm air heating plants for the purpose of circulating the warm air through the heating system to the registers in the rooms.

In the conventional type of fan used with warm air heating plants the air is taken into the fan through air inlets provided at each end of'the fan housing and is discharged through a discharge opening in the front side of the housing which is disposed at right angles to the air inlets. The discharge opening is usually much larger than the air inlets. A considerable volume of air is required to fill the fan housing and to provide the amount necessary to circulate the warm air through the heating system. With the conventional type of fan having air inlets only in the ends of the housing, inorder to obtain a sufficient volume of air to fill the housing the air is drawn into the fan with considerable force. The air which is drawn in through the inlet in oneend of the housing engages the air which is drawn in through the opposite inlet and both streams of air are deflected at right angles and are discharged through the discharge opening. Because of the force with which the air is drawn in at each side of the housing, the two streams of air come together within the housing with a sudden impact. This sudden meeting of the two streams of air within the fan and the deflection of their course towards the discharge opening causes a resistance to be set up within the fan wheel which tends to reduce the speed of the fan. This necessitates increasing the driving power so that the fan may be rotated at the proper speed.

The object of the present invention is to eliminate, as far as possible, the'friction or resistance in the fan wheel, thereby permitting the fan to be operated with much less power and therefore at a minimum of expense.

Another object is to provide a structure of this kind which is efiicient in operation and of a design which is economical to manufacture.

Other objects and advantages of my invention will be apparent to those skilled in the art after a consideration of the following detailed description, taken in conjunction with the accompanying drawing wherein:

Figure 1 is a side elevational view of a complete blower fan structure illustrating my improvement;

Figure 2 is a top plan view of the structure shown in Figure 1;

Figure 3 is an enlarged sectional view taken substantially on the plane of line 2; and

Figure 4 is a detail section taken on the, plane of line 4-43 of Figure 3.'

The fan comprises'a housing 6 having a pair of end members 1 which are held in spaced parallel relation by an arcuatehood. member 8. The hood member 8 is riveted or otherwise secured to the outer peripheral edges of the end members 1. The end members i are each preferably constructed of a single sheet of metal which is formed in the desired shape. The ends of the hood members 8 and members i are disposed in the usual manner-to form a discharge opening ll through which the air is discharged.- A primary air inlet l2, shown in Figure l, is provided in each end member 1 and these inlets serve to admit a portion of the air which is drawn into the fan. The

3-3 of Figure inlets l2 are of the usual type such as are'commonly used with the conventional blower fan. The housing 6 is supported on legs l3 which are securely fixed to the housing and to a base or platform Hi. A plurality of auxiliary air inlets I5 are provided in the top of hood member 8 adjacent the forward portion thereof, for a purpose to be later described. The inlets l5 extend transversely across the hood member 8 and are of a length equal to the width of the housing 6.

r The air inlets l5 are preferably of graduated size, the larger opening being disposed at the front and the smaller one at the rear as shown in Figure 3. The auxiliary air inlets l5 would function just as efilciently if they were all of the same size as do those in the preferred form. However, it has been found in practice that the greater amount of air is taken in through the forward inlets, therefore the larger openings are not needed in the rear inlets. The inlets I 5 are formed by providing a plurality of steps or offset portions in the end members i which are connected by transversely extending louver boards l6 which are secured to corresponding or transversely disposed steps on the end members 1. The inner or rear edge 16a of each louver board extends inwardly beyond the outer or front edge of the next adjacent board to form an air passage for the admission of air to the housing 6.

A fan wheel or rotor I1 is rotatably mounted in the housing 6 and is supported on a drive shaft I8 which is journaled in bearings l9 disposed at each end of housing 6. Each bearing i9 is mounted on' the horizontal portion of an inverted U-shaped bracket 2!, the vertical legs of which are bolted or otherwise secured to the upper ends of the supporting legs IS. The bearings l9 are preferably of the self-aligning type such as are illustrated and described in my Patent Number 2,001,383, which issued May 14, 1935. The rotor l1 comprises a pair of fan wheels or wheel sections 22 which are secured together so as to rotate as a single unit. The inner end of each wheel section 22 is formed of a disk member 23. A central opening is provided in each member 23 to permit the wheel sections 22 to be passed over the shaft l8. The inner adjacent ends of the wheel sections are secured to opposite sides of a circular flange 24, which is fixed on the shaft l8, by means of bolts 25 which extend through aligned holes in the disk members 23 and flange 24. A plurality of arcuate shaped fan blades 26 are equidistantly spaced around each disk member 23 adjacent the outer edge thereof. laterally from the disk members 23 the outer ends being rigidly secured to ring members (not shown). The rotor H is driven by an electric motor 3| which is mounted on base I4 through a drive belt 32 engaging over pulleys 33 and 34 fixed respectively on the motor drive shaft and on shaft l8.

In the operation of my improved type of fan the rotor i1 is driven by the motor 3i through the drive belt 32. The rotating action of rotor 11 serves to draw air into the fan through the openings i 2 which are disposed in the end sheets '1 adjacent the ends of the rotor. The centrifugal action of rotor l1 pushes the air, which is in the fan, outwardly through the openings between the fan blades 26 into the housing 6 from which it is discharged through the discharge opening H. As the air is discharged off the outer periphery of the blades 26 it is given a whirling motion around the wheel 11. This whirling motion serves to draw air into the housing 6 through the auxiliary air inlets [5. The inlets l5 are preferably located in the upper, forward portion of the hood 8, as shown, since this is the position nearest the rotor I! and therefore where the suction will have the greatest eiiect. It will be apparent that the air which is drawn in through the auxiliary air inletsi5 is taken in by the injection principle. This air is passed directly around the fan to the discharge opening or outlet II without the necessity of changing the direction of course such as is necessary with the air taken in through the primary air in ets l2 thus giving the air a streamline movement through the fan. It has been found that the air, drawn in through the inlets I5, may be passed around the fan housing to the outlet H with practically no resistance to the fan wheel l'i. This arrangement, therefore, permits the same volume of air to be discharged as with the previous type of fan, but with a reduced load on the motor or with a motor of smaller horse power. From the description given it is thought that the operation and the utility of my present structure will readily be understood by all familiar with this art.

In this static pressure air blower the air inlet openings i5 are located adjacent the air cut off b Fig. 3 in the forward portion of the hood member 8 Fig. 3, only, for a very specific reason. The sucking action of the air leaving the periphery of the wheel HFig. 3 is greatest just afterpassing the cut oil "12 Fig. 3 and diminishes as the distance between the periphery of the wheel I! Fig. 3-and the housing 8 Fig. 3 increases until at the average operating efficiency deadline a Fig. 3 beneficial action upon the These blades 26 extend outward secondary air inlets by the air leaving the periphery of the wheel I'l-Fig. 3 practically ceases while operating under normal conditions and resistances as of present day air conditioning practice. 5

The auxiliary air inlet opening nearest the air cutoif b" in housing 8 Fig. 3 does the biggest job while the opening nearest the average operating efficiency deadline a Fig. 3 does very little work. It can now be seen why it was considered desirable to graduate the size of the auxiliary ducts in proportion to the amount of work done by each. It auxiliary air openings are placed beyond the average operating efliciency deadline a Fig. 3 said openings will serve as outlets for the compressed air whenever resistance is applied at the discharge opening il-- Fig. 3 in direct proportion to the location of the auxiliary air openings, the openings farthest from the cut oil b Fig. 3 and nearest the front bottom of the discharge opening ii Fig. 3 will discharge the most air thereby tending to create an undesirable condition and the exact opposite to results obtained by my new discovery.

If the air blower is not to be operated against 25 static pressure, auxiliary air inlets could be placed somewhat beyond the average operating deadline a Fig. 3 without detrimental results, however as my air blower is designed as a blower to operate against static pressure I am not concerned with free air operating conditions because, my blower design having auxiliary air inlets placed between the air cutoff "b Fig. 3 and the average operating deadline "a Fig. 3 will op- ;erate efilciently with or without static pressure,

while if auxiliary air openings are placed beyond the average operating deadline a" Fig. 3, designating the air cutoif b" Fig. 3 as the starting point the air blower will not operate emciently while under static pressure as the openings will 40 then reverse themselves and become 'air outlets instead of auxiliary air inlets.

It can now be seen why it is impossible to place auxiliary air inlets beyond the deadline "a" in housing 8 Fig. 3 in an air blower operating under static pressure and have efficient, satisfactory operation at maximum capacity.

It is to be understood, as a matter of course, that the present invention does not require the employment of auxiliary air inlets constructed precisely as described, but that, in fact, widely different means may be employed in the practice of the broader aspects of my invention.

What I claim, therefore, and desire to secure by Letters Patent is:

1. An air blower comprising a rotor, a housing having end members disposed at opposite ends thereof, primary air inlets in said end members, an arcuate hood member, a plurality of offset step portions formed in each end member adiacent the air cut oil. on the housing and not beyond the designated efficiency dead line, said step portion in one end member being in transverse alignment with corresponding step portions in said other end member, and a plurality of louver boards secured to said corresponding transversely aligned step portions in said end members, the inner edges of said louver boards projecting inwardly beyond the forward edges of the next adjacent louver board to form air passages into said housing and a discharge opening for discharging air from said housing.

2. A pressure building air blower comprising a housing, a rotor, a driving means, primary air inlets in the ends 0! said housing, auxiliary air housing, a rotor, a driving means, primary air.

' aosasse inlets intheendsofsaidhousingpauailiaryair inlets in said housing located adjacent the air out oi! thereof and between said air out oi! and the designated approximate emciency dead line.

said auxiliary air inlets tobe graduated in sine and air capacity. the largest and greatest capacity opening to be adjacent the said air out of! and the smallest and of least capacity opening to be adjacent the said approximate emciencydead line and a discharge opening {or discha ging air 1 from said housing.

EDWARD A. mm. 

